Catheter embolization of pulmonary arteriovenous fistulas in an infant

Summary An infant with pulmonary arteriovenous fistulas is described. Surgical ligation of the fistulas and limited resection of paraenchyma from the right lung was followed at 11 months of age, by successful steel coil embolization of residual fistulas.     

Reversible reorganisation of the motor cortical representation of the hand in cervical dystonia.

Previous work has suggested that there may be a widespread disturbance of motor control mechanisms in patients with cervical dystonia. In the present study, we used transcranial magnetic stimulation to investigate the topography of the corticomotor projection to the abductor pollicis brevis (APB) muscle in 10 subjects with idiopathic torticollis. Threshold-adjusted stimuli were delivered at multiple scalp sites during a low-level voluntary contraction of the APB, and maps were generated of motor evoked potential amplitude versus scalp site. The cortical maps for the APB on the side opposite to the direction of head rotation were displaced laterally or posteriorly in all subjects and reverted to a more normal position after botulinum toxin injection of the cervical muscles in 5 subjects. The findings point to a reversible reorganisation of the corticomotor representation of the hand on the same side as the sternocleidomastoid (SCM) muscle that is involved in producing the dystonia. These results provide further evidence for the involvement of cortical centres and for a more widespread abnormality of motor control mechanisms in focal dystonia. The findings also support the notion that head turning is chiefly mediated by the hemisphere ipsilateral to the direction of the head rotation by means of a corticomotor projection to the contralateral SCM.     

Local variations in the cerebral microcirculatory response to hypercapnia and haemorrhage

Summary This study evaluates local variations of the cerebral vasomotor responses to hypercapnia and haemorrhagic hypotension in a pig model. Four laser Doppler flow probes were used in each pig. There was considerable variation in laser Doppler signals between the four probes in baseline recordings. The increases in flow after CO₂ administration in 7 pigs had a mean coefficient of variation of 0.43 ± 0.31, and the flow changes after blood loss in another 7 pigs had a mean coefficient of variation of 0.45 ± 0.34. The range of flow changes within each animal was large; the probe with the highest CO₂ response showed on the average a 273% ± 157% larger CO₂ response than the probe with the lowest CO₂ response. Correspondingly, the probe with the best preserved blood flow after blood loss had on the average a flow value of 93% ± 12% of the baseline value, while the probe that changed most with haemorrhage had a flow value of 44% ± 24% of the baseline value. Single laser Doppler recordings have been used for the monitoring of cerebral blood flow in neurosurgical critical care, but our results suggest that a single laser Doppler flow probe is not an adequate method to monitor vasoreactivity in neurosurgical patients because flow signals from one probe may be unrepresentative for other sites in the brain.     

Experimental model of chronic tonsillar herniation associated with early stage syringomyelia

This report describes an experimental model of chronic tonsillar herniation and its effects on the spinal cord. In ten rats, a small piece of chemically induced mammary cancer was transplanted to the supraoccipital bone. In all cases, the transplanted cancers grew into the posterior fossa, destroying the supraoccipital bone and compressing the cerebellum extradurally. In six of the ten rats, tonsillar herniation was observed at 8–14 weeks after transplantation. Transdural infiltration of the tumor cells was not apparent in any animal. In those rats with tonsillar herniation (n=6), the spinal cord from the C5 to the T8 segments showed enlargement of the central canal without exception. Histological examination revealed the following changes: stretching and thinning of the ependymal cells; swelling of the astrocytic processes; and extracellular edema, predominantly in the dorsal gray matter, but also in the ventral inner portion of the dorsal column. In the control group (n=4) and those rats without tonsillar herniation (n=4), such histological changes of the spinal cord were not observed. Although the lesions can not be regarded as representing mature syringomyelia, they most likely constitute an earlier evolutionary stage.     

硫酸镁联合亚低温治疗对大鼠局灶性脑缺血的保护作用

目的　探讨硫酸镁对SD大鼠局灶性脑缺血损伤的保护作用。方法　将 4 0只大鼠随机分成模型对照组、硫酸镁治疗组、亚低温治疗组、硫酸镁联合亚低温治疗组。采用线栓法建立大鼠局灶性脑缺血模型。通过计算大鼠神经功能缺陷评分 ,测量脑梗死体积 ,观察神经元超微结构改变 ,评定硫酸镁联合亚低温治疗作用。结果各治疗组大鼠神经功能评分及脑梗死体积均显著低于对照组 (P <0 0 5 ) ,联合治疗组大鼠明显低于对照组 (P<0 0 1) ;联合治疗组神经元超微结构改变轻微。结论　硫酸镁联合亚低温治疗对大鼠局灶脑缺血有明显保护作用     

Distributive profiles of free and protein-incorporated tryptophan and valine in cerebral cortex slices from adult and 2-day-old rats

The distribution of the specific radioactivity and the incorporation into protein of [³H]-tryptophan and [³H]valine at varying layers from surface to centre were measured in incubated slices of cerebral cortices from infant and adult rats. Specific radioactivity in free amino acids was in both age groups highest in the intact surface layer. Incorporation of tryptophan into protein was even in slices from adult rats but much less than the average in the surface layers in slices from infant rats. Incorporation of valine exhibited similar heterogeneity in both age groups. The results suggest in brain slice preparations a zonal compartmentation of amino acid and protein metabolism which varies for different amino acids.     

高血压鼠局部脑梗塞后脑超微结构改变动态观察

本文选用肾血管性高血压鼠(RHR)复制大脑中动脉闭塞(MCAO)模型,其后2h至7d分8次取不同区域脑组织进行透射电镜动态观察超微结构的改变。显示局部脑梗塞后发生全脑性改变,其损害程度和出现时间梗塞区最早,以坏死为主,呈完全不可逆性损害;边缘区稍后,主要是微血管塌陷和微血栓形成及部分脑细胞坏死,呈部分可逆性损害,远隔区和镜区最迟,以内皮和星形细胞水肿为主,呈可逆性损害,认为用RHR复制MCAO,更接近于高血压性脑血管损害基础上发生脑梗塞的临床病理改变,全脑超微结构的动态性改变中微血管损害起着重要作用。     

156例脑梗塞的临床分析

本文报道脑梗塞患者156例,就其发病情况,诱发因素,临床特点,治疗及预防进行了分析讨论。脑梗塞的发病高于脑出血,高血压动脉硬化是发生脑梗塞的主要危险因素。积极预防和治疗高血压有极其重要的意义。脑梗塞的治疗应根据脑水肿的情况进行,不宜普遍首先应用扩血管治疗。本病复发率高,反复发作可引起广泛性脑部损害,其病死率、病残率明显高于首次发病。小剂量阿斯匹林等药物应用对预防复发可能有一定作用。